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> Fuel Injector voltage?
RustyWa
post Jul 30 2004, 04:43 PM
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I did a quick search but could not find the info.

At what voltage and milliamps do the injectors run at when powered from the ECU? I was doing a test on mine and one injector wasn't firing like the others.
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Dave_Darling
post Jul 30 2004, 05:17 PM
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Check on Brad Anders website. They get a pretty good-sized spike initially, which then drops off to about 5V, I think. Not sure how much current they need.

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Mark Henry
post Jul 30 2004, 05:18 PM
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about 2.5 volts will kick it
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McMark
post Jul 30 2004, 09:19 PM
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(IMG:style_emoticons/default/agree.gif)

Full 12v is supposed to be bad for them, but everyone I've talked to about it has used it with no problem (me included). Not saying it's a smart idea though.
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newdeal2
post Jul 30 2004, 09:49 PM
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FYI I just had my fuel injectors cleaned and balanced...I got a full test chart back with the injectors. They did the job fast too.

See http://www.injector.com/

Peter
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RustyWa
post Jul 30 2004, 10:28 PM
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I'll check Brad's site again.

I started off with a 1.5 volt "AA" battery. That triggered all but 1 of the injectors. So I up'd it to a 1.5 volt "D" size. Still no go. Tried a 9v. It would fire, but if I pressurized the inlet side of the injector with liquid, it would not fire. This one injector also had a different name on it. "RAM" is the only identifying mark on it, but it is green in color.

It also appeared that all my injectors just squirted a stream. No "cone". Looks like a professional cleaning is in order.
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McMark
post Jul 31 2004, 12:12 AM
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I know there was a company called RAM that rebuilt MPSs.
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newdeal2
post Jul 31 2004, 10:45 AM
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Go to Marren as I did , they are very good.

I put the link on my last message.

Peter
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KitCarlson
post Jul 31 2004, 09:05 PM
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With the 6 ohms series resistance in the D-Jet assuming the drive transistor is saturated, the voltage at a low impedance injector with a resistance of 2.3 ohms is approximatel equal to 13.8 * 2.3 / ( 6 + 2.3 ) = 3.8 volts, with an ON current of ~ 1.65 amps. The 13.8 is the assumed battery voltage.

The opening time decreases with supply voltage, however the closing time increases if the holding current is high.
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McMark
post Aug 1 2004, 02:06 AM
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Damn Kit, you talk like you know what you're doing!

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davep
post Aug 1 2004, 05:49 AM
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Kit, what you indicate is that the fuel delivery would be "system voltage" dependant. So if there is problems in the electrical system, high / low voltage, then the engine would essentialy be out of tune? Would a voltage regulator designed into the ECU be useful to ensure a constant voltage?
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RustyWa
post Aug 1 2004, 01:38 PM
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QUOTE(KitCarlson @ Jul 31 2004, 07:05 PM)
With the 6 ohms series resistance in the D-Jet assuming the drive transistor is saturated, the voltage at a low impedance injector with a resistance of 2.3 ohms is approximatel equal to 13.8 * 2.3 / ( 6 + 2.3 ) = 3.8 volts, with an ON current of ~ 1.65 amps. The 13.8 is the assumed battery voltage.

The opening time decreases with supply voltage, however the closing time increases if the holding current is high.

That's some good stuff. Thanks!
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KitCarlson
post Aug 1 2004, 07:58 PM
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davep,

Yes there is voltage compensation in the EMS. One of the parameters the EMS measures is the battery voltage. It is important both for ignition dwell control and injector pulse width correction.

Enough secrets for today.

Kit (IMG:style_emoticons/default/biggrin.gif)
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PorscheTom
post Aug 2 2004, 11:43 AM
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Hello Kit,

Any ETA on the 914 EMS kit?
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pbanders
post Aug 2 2004, 12:34 PM
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http://members.rennlist.com/pbanders/ecu.htm#D1-D2

The sustained voltage drop across the injector is 3 V. It initially drops system voltage (~13V) across it when turned on, but once the inductive reactance drops there's a resistor in series with it that results in a 3 V steady state voltage.
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